Rope sheave for venetian blinds



July 19, 1938. E. REUKAUF. JR

ROPE SHEAVE FOR VENETIAN BLINDS Filed June 2, 1956 EJwarcYBeuAaaf J1 yEs/%2fl Patented July 19, 1938 PATENT OFFICE ROPE SHEAVE FOR VENETIAN BLINDS Edward Reukaui, In, Philadelphia, Pa., assignor to Carey-McFall 00., Philadelphia, Pa., a corporation of Pennsylvania Application June 2, 1936, Serial No. 83,111

5 Claims.

This invention relates to a rope sheave for use in a Venetian blind, and the primary object of the invention, is to keep the rope from slipping or creeping on and relative to the sheave.

The rope and sheave form part of the slattilting mechanism of the blind and when the slats of the blind are in their normal horizontal positions, permitting the maximum amount of light or air to pass through the blind, the central part of the tilting rope or cord is normally passing around and lying on the upper half portion of the sheave, leaving the two ends of the rope or cord hanging down freely and equally from opposite sides of the sheave with the ornamental tassels or other weighted ornaments normally found on the ends of Venetian blind ropes disposed at substantially the same level.

The slats are adapted to be tilted from the horizontal position to any desired angle between the horizontal and vertical by pulling downwardly on one of the depending ends of the rope. The opposite end of the rope is pulled downwardly to return the slats to their normal horizontal positions or for tilting the slats in an opposite direction with respect to the horizontal.

In order to exclude the maximum amount of light or air the slats are usually tilted in the same direction each time, and the tilting is usually continued until the lower edge of each slat lies in overlapping relation to the upper edge of the next lower slat. The tilting mechanism is so constructed that when the maximum angle of tilt of the slats with respect to the horizontal is achieved rotation of the sheave is arrested and it is common practice for persons, when desiring to tilt the slats to their fullest extent, to jerk the one end of the tilting cord more or less violently which, when the rotation of the sheave is arrested, as above noted, results in the rope slipping or creeping on and relative to the sheave. However, when the opposite end of the rope is pulled to return the slats tothe normal horizontal position, or to tilt the slats in an opposite direction to the horizontal, to permit more air or light to pass through the blind, the operation is usually effected with more care than is exercised when tilting the slats to the full closed position, as a result of which no substantial amount of return slippage between the rope and sheave is effected which would compensate for the slippage occurring when the first said end of the cord was violently pulled in tilting the slats to the maximum light and air extruding positions. Repeated operation of the slats in this manner eventually results in the one end of the cord hanging down to a considerably greater extent than the other end of the cord when the slats are in the normal horizontal position.

The sheave wheels of Venetian blinds hereto- {ore have been provided with a plurality of protuberances extending inwardly from the opposite walls of the rope-receiving groove of the sheave and arranged in staggered relation to each other to cause the rope to pass around the upper side of the sheave in a more or less zig-zag manner to provide a sort of snubbing action on the rope, with a view of eliminating creeping of the rope relative to the sheave. Such means, however, has in practice proven to be inadequate and while this arrangement may reduce the slippage to some extent nevertheless the rope eventually becomes unbalanced in the manner above noted.

The object of the present invention is to replace the snubbing action on the rope with a pinching and locking action by arranging the laterally extending protuberances in opposition to each other and by providing the sheave with means disposed in the rope-receiving groove intermediate the oppositely extending protuberances axially and circumferentially of the sheave and arranged to pierce the surface of the rope. Such arrangement has in practice been found to eliminate the creeping or slipping of the rope relative to the sheave satisfactorily.

Another object of the invention is to provide a guard around at least a portion of the periphery of the sheave for keeping the rope from jumping out of the groove of the sheave when the sheave is stopped suddenly, by reason of the slats attaining the full maximum closed position; and to mount the guard in such a manner that it will pivot freely about the axis of the sheave without binding on the rope regardless of the angle at which the depending end of the rope may be pulled, in the plane of the groove, when operating the slats.

A Venetian blind to which the present invention is particularly applicable is shown and described in the copending application of Walter J. Stuber, Serial No. 52,725, filed December 3, 1935.

The construction and operation of the device forming the subject of the present invention will be fully disclosed hereinafter, reference being had to the accompanying drawing, of which:

Fig. 1 is a side elevation of the slat-tilting mechanism drawn to an enlarged scale;

Fig. 2 is a transverse sectional elevation taken on the line Z- -E, Fig. 1;

Fig. 3 is a sectional elevation taken on the line 3-3, Fig. 2;

Fig. 4 is an edge view of the sheave with the rope in section;

Fig. 6 is an edge view of a modified form of rope-piercing means; and

Fig. 6 is a side view of the elements shown in Fig. 5.

As shown in Fig. '1, the tilting bracket of the Venetian blind is illustrated at I. Pivoted at 2 to the bracket I is a substantially 180 segment of a worm wheel 3. The segment 3 is provided with a flange or other means 4 for supporting the tilting rafl 6 of the Venetian blind and to which the slat-supporting tapes 6, 6 are secured. The slats 'I are carried between the tapes 6, 6 in the usual mannerby the ladder tapes 8.

Meshing with the teeth of the worm wheel segment 3 is a two-part worm 9, which is disclosed in detail in the above noted copending application. The worm wheel 9 is secured to one end of the tilting shaft III, which latter is rotatably mounted in bearings II formed in the bracket I.

Secured to the opposite end of the shaft III is the rope sheave I2. The rope sheave I2, in the present instance, is composed of two similar circular discs I3, I3. The peripheral marginal edges of the discs I3, I3 are flared outwardly in opposite directions or otherwise spaced apart laterally to provide a circumferentially extending rope-receiving groove I4 in the sheave I2.

At angularly spaced intervals, and extending radially from the axis of the shaft I0, each of the discs I3 is provided with a series of inwardly extending protuberances I5, I5, each of which is smoothly rounded or otherwise formed on its inner surface where it projects into the ropereceiving groove I4. The protuberances I5 of the one disc are arranged in direct opposite relation to the protuberances of the other disc to cause the portion of the rope I6 which lies within the circumferential groove I4, when tension is applied to either end of the rope, to be pinched between the inner surfaces of the opposed pairs of protuberances I 6.

The pinching action produced by the protuberances I5 while it aiIords a gripping of the rope which when the slats are tilted with a reasonable amount of care would preclude relative slippage between the rope and the sheave does not eliminate creeping of the rope relative to the sheave under abnormal circumstances as noted and in accordance with the present .invention the sheave is provided with a series of rope-piercing points I! which extend or project into the groove I4 and engage and pierce the surface of the rope I6 tolock the rope definitely to the sheave throughout that portion thereof which lies in the groove and passes around the axis of the shaft I0.

In the present instance; the rope-piercing points II are formed as part of a disc I8 which assumes the shape of a star wheel and which is disposed intermediate the two sheave-forming discs I'3, I3. The points II, II project radially with respect to the axis of the shaft III intermediate the protuberances I5, I5 formed on the inner walls of the outwardly flaring peripheral marginal edges of the discs I3.

The star wheel I8, as shown in Fig. 3, is gripped firmly between the central portions I9, IQ of the I3 is composed are each provided with corre-v spondingly shaped apertures fitting snugly over the flattened end 26 of the shaft. II to key the sheave, including the star wheel, to the-shaft. The outer end of the shaft is riveted overthe outermost of the discs I3 for rigidly securing the sheave in place on the shaft.

Intermediate the innermost disc I3 and the outer edge 22 of the bracket I the shaft I0 is provided with a diametrical enlargement 23 which may be in the form of a sleeve having a pressed fit on to said shaft or, if desired, loosely encircling the shaft, and which maintains definite spaced relation between the sheave I2 and the outer edge 22 of the bracket I.

Loosely mounted on the shaft enlargement 23 is the hub 24 of the guard 26. The guard 26 comprises, in addition to the hub 24. a back plate 26 which is disposed between the sheave I2 and the outer edge 22 of the bracket I. The back plate 26 of the guard 26 is provided with a pair of oppositely disposed flanges 21, 21 which extend substantially at right angles to the plane of the back plate 26 outwardly across and transversely with respect to the rope-receiving groove I4 of the sheave I2, said flanges, while bein spaced sufiiciently from the peripheral edge 23 of the sheave I2 to prevent actual engagement therebetween, are spaced close enough to said peripheral edge to prevent jumping of the rope I6 out of the groove I4 upon either end of the rope being jerked suddenly or if rotation of the sheave is stopped suddenly in the manner above noted.

The free loose mounting of the hub 24 of the guard 25 on the sleeve 23 and the length of the enlargement formed by the sleeve 23 of the shaft III being in excess of the length of the hub 24 permits the guard to swing to anv desired position about the axis of the shaft I0 without binding on'therope I6 or against the sheave I2 or edge 22 of the bracket I. i

In the form illustrated in Figs. 1 to 4 the star wheel at I3 is fiat throughout its entire area including the points II which engage the rope in the same general plane of the wheel at all times. In the form the star wheelIBa assumes in Figs. 5 and 6 the points "a are alternately bent in opposite directions from the general plane of the wheel and engage the rope on opposite sides of the central longitudinal plane thereof, thus distributing the piercing action of a greater area of the hope. In some instances the laterally bent points I'Ia. may be interspersed with or among straight radial points I! in a single star wheel,

if desired, to distribute'the piercings of the rope to a still greater extent.

I claim:

1. A rope sheave for Venetian blinds comprising a plurality of axially aligned discs having the marginal edges of the countermost discs of said plurality disposed in laterally spaced relation to ,each other providing a rope-receiving groove therebetween and a series of rope-piercing points on an intermediate disc of said plurality projecting into said groove.

2. A rope sheave for Venetian blinds comprising a pair of similar discs arranged in axially aligned substantially parallel relation to each other and having laterally spaced marginal edges providing a rope-receiving groove therebetween, and a star wheel intermediate and axially aligned with said discs and provided with a series of ropepiecing points projecting into said groove.

3. A rope sheave for Venetian blinds comprising a pair of similar discs arranged in axially aisaavo discs and projecting laterally into said groove, 7

and a star wheel intermediate and axially aligned with said discs and provided with a series of rope-piercing points projecting into said groove intermediate said protuberances. I

4. A rope sheave tor Venetian blinds comprising a pair of similar discs arrangedin axially aligned substantially parallel relation to each other and having laterally spaced marginal edges providing a rope-receiving groove therebetween. a series or rope-engaging protuberances on said discs and projecting laterally into said groove. and a star wheel intermediate and axially aligned with said discs and provided with a series oi ropepiercing points projecting into said groove intermediate said protuberanees with predetermined points of said series extending laterally from and at an angle to the plane of said wheel.

5. A rope sheave for Venetian blinds comprising a pair of similar discs arranged in axially aligned substantially parallel relation to each other and having laterally spaced marginal edges providing a rope-receiving groove therebetween, a series of rope-engaging protuberances on said discs and projecting laterally into said groove and arranged in laterally opposed pairs transversely of the groove, and a star wheel intermediate and axially aligned with said discs and provided with a series of rope-piercing points projecting into said groove intermediate said protuberances.

EDWARD REUKAUF, Js. 

